Field of the Invention
The invention relates to a hinge device capable of extending rotational angle, and more particularly to a hinge device for stands of electronic devices opening to a marge angle stably and reliably.
Description of the Related Art
Since mobile devices such as tablets are often held by both hands, a user who uses the mobile devices is easily tired. The mobile devices put on thigh are easily to slide, which may bother the user. To solve the problem, a stand is attached to the mobile devices and the mobile device can be set upright by the stand for stable and convenient operation.
The stand is pivoted to the mobile devices at one end, and the other end is free. When the stand is not to be used, it can be folded and accommodated on the back of the mobile devices. When the stand is used, it can be rotated about the pivoted end and opened to various angles. Since the stand must also positioned at desired angle, the pivoted end often includes a hinge device having rotational mechanism and positioning mechanism. However, conventional hinge devices can only be rotated to a small angle and have a mechanism of high freedom, which causes the mobile device unstable when it is used.